I'd argue against this. I always saw through password-guessing as fake and not really understanding anything when I was young, but lacked the people skills to notice that the teachers and examiners wanted me to guess the password rather than demonstrate that I really understood (because I didn't understand why), and lost a few exam marks along the way to figuring that out!
Password-guessing skills are the lowest hanging fruit in terms of improving grades; your experience seems to support that as well.
So-called "test skills", which improve performance on tests without improving mastery of the nominal subject of the test, are strong evidence of inefficiency in the school system. Are you proposing remaking the entire game of quittich instead of getting the bludgers better brooms?
In about eight months or so, I will be one of those (hopefully not starving) students. I'll be moving out to London to live with my aunt and uncle in a rather nice middle-class neighbourhood, while I study and work to prepare for university the following year. They know a lot of the parents around there and suggested that I begin teaching small groups of 8-to-12 year old children for maybe an hour or two regularly, and charge their parents/guardians a reasonable sum per child. I would be teaching them math and science in all likelihood. Apparently word will get around quickly if I'm competent so I might have a substantial number of customers within a few months.
My questions: